Medical tube position confirmation system

ABSTRACT

A medical tube position confirmation system for confirming the position of a medical tube that is used to supply nutrients to the interior of a body by means of tube feeding while an end portion thereof is inserted into (placed in) the stomach includes a light guide that is configured to guide light entering through an incident end portion so that the light exits through an exit end portion, and is configured to be insertable into the medical tube so that the exit end portion is disposed in the interior of the stomach, and a light source that is optically connected to the incident end portion of the light guide and emits light containing wavelengths that pass through a living body.

TECHNICAL FIELD

The present invention relates to a medical tube position confirmationsystem.

BACKGROUND ART

Conventionally, in a medical setting, food is supplied directly into thestomach of a patient who finds oral ingestion of food difficult using amethod known as nasal tube feeding. More specifically, a soft nasal tubeis inserted through the nasal cavity of the patient until a tip endportion thereof reaches the stomach, whereupon liquid food andnutritional supplements are injected through a base end portion of thetube.

During nasal tube feeding, a method of inserting a nasal tube coatedwith lubricating jelly into the nostril, having the patient perform aswallowing action repeatedly while feeding the tip end portion of thetube more deeply little by little, and guiding the tip end portion ofthe nasal tube toward the esophagus side until the tip end portionreaches the stomach is implemented.

However, the back of the throat of a human bifurcates into two passages,namely the trachea and the esophagus, making the operation to insert thenasal tube extremely difficult, and when food or the like enters thelungs mistakenly, aspiration pneumonia or the like may occur. It istherefore necessary to perform an operation to confirm that the tip endportion of the nasal tube has reached the stomach.

Patent Document 1 discloses a detection line having a pair of insulatedwires and a sensor portion formed on the tip end thereof. The detectionline is inserted into a medical tube so that when the sensor portioncomes into contact with gastric juice, a resistance value between thepair of insulated wires varies. Hence, by detecting variation in theresistance value between the pair of insulated wires, it can bedetermined that the sensor portion has come into contact with gastricjuice and accordingly that the medical tube has correctly reached thestomach.

Further, Patent Document 2 discloses a nasal tube tip end positionconfirmation device including a casing, a connecting portion thatcommunicates with the outside from the casing and is connected to a baseend side of a nasal tube inserted into the body of a patient, a sensorelement disposed in the casing, an electronic circuit, and displaymeans. The electronic circuit outputs air pressure variation received bythe sensor element in the form of an electric signal, and the displaymeans receives the output from the electronic circuit and displays theair pressure variation in a recognizable state. Hence, by pressing theabdomen of the patient from the outside, air pressure variation isgenerated in the stomach, and by having the display means displayinformation indicating that the sensor element has received the airpressure variation, it is possible to determine whether or not the nasaltube has been inserted to an appropriate position.

CITATION LIST Patent Document

Patent Document 1: Patent Publication JP-A-2016-77450

Patent Document 2: Japanese Patent No. 6245870

SUMMARY Technical Problem

However, with a method employing a detection line, such as that ofPatent Document 1, it is necessary for gastric juice to be secreted inan appropriate location. This means that the types of patients to whichthe method can be applied are limited, and runs counter to the aim ofdetermining the position of the medical tube with precision. Further,with a method employing air pressure variation, such as that of PatentDocument 2, a complicated configuration is required to control the airpressure, leading to an increase in manufacturing cost.

An object of the present invention is therefore to provide a medicaltube position confirmation system with which the position of a medicaltube can be confirmed more easily.

Solution to Problem

A medical tube position confirmation system according to an aspect ofthe present invention is a medical tube position confirmation system forconfirming the position of a medical tube that is used to supplynutrients to the interior of a body by means of tube feeding while anend portion thereof is inserted into (placed in) the stomach. The systemincludes a light guide that is configured to guide light enteringthrough an incident end portion so that the light exits through an exitend portion and is inserted into the medical tube so that the exit endportion is disposed in the interior of the stomach, and a light sourcethat is optically connected to the incident end portion of the lightguide and emits light containing wavelengths that pass through a livingbody.

According to this aspect, the light emitted from the light source, whichcontains wavelengths that pass through a living body, is guided throughthe interior of the light guide inserted into the medical tube so as toexit through the exit end portion of the light guide, which is disposedin the stomach. Having exited through the exit end portion, the lightthen passes through the stomach and the living body. Hence, an operatorcan confirm the position of the medical tube by checking the position inwhich the light passes through the stomach and the living body from theexterior of the living body.

Advantageous Effects of Invention

According to the present invention, it is possible to provide a medicaltube position confirmation system with which the position of a medicaltube can be confirmed more easily.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a pattern diagram showing an example of a configuration of amedical tube position confirmation system 1 according to an embodimentof the present invention.

FIG. 2 is a schematic view showing an example of a functionalconfiguration of a light 10.

FIG. 3 is a view illustrating wavelengths of light emitted by the light10.

FIG. 4 is a schematic view showing an example of a functionalconfiguration of a camera 30.

FIG. 5 is a schematic view showing an example of a functionalconfiguration of a user terminal 40.

DESCRIPTION OF EMBODIMENTS

Referring to the attached figures, a preferred embodiment of the presentinvention will be described (note that in the figures, identicalreference numerals denote identical or similar configurations).

(1) Overall Configuration

FIG. 1 is a pattern diagram showing an example of a configuration of amedical tube position confirmation system 1 according to an embodimentof the present invention. As shown in FIG. 1, the medical tube positionconfirmation system 1 includes, for example, a light 10, an opticalfiber 20, a camera 30, a user terminal 40, and a database 50. The userterminal 40 is connected communicably to each of the light 10, thecamera 30, and the database 50 via a communication network.

(2) Configurations of Respective Parts

(2-1) Light 10

FIG. 2 is a schematic view showing an example of a functionalconfiguration of the light 10. The light 10 is an example of a lightsource that emits light containing wavelengths that pass through aliving body. The light 10 is formed by providing a light-emitting unit11, a drive circuit 12, a processing unit 13, a storage unit 14, and acommunication unit 15 in a substantially cylindrical casing formed frommetal, resin, or the like, for example.

The light-emitting unit 11 is constituted by a light-emitting LED, forexample, and emits light containing wavelengths that pass through aliving body. When the light 10 receives a supply of electric energy froma power supply (not shown) via the drive circuit 12 while a switch (notshown) provided on the light 10 is switched ON, the light 10 emits lightof predetermined wavelengths by converting the electric energy intooptical energy. Note that the light-emitting unit 11 is not limited to alight-emitting LED and may be any light-emitting body that emits lightcontaining a wavelength that passes through a living body.

The light 10 is optically connected to an incident end portion 20I ofthe optical fiber 20, to be described below, so that the light emittedby the light-emitting unit 11 of the light 10 enters the incident endportion 20I of the optical fiber 20.

The processing unit 13 is a CPU or the like, for example, having one ora plurality of processors and corresponding peripheral circuits, andperforms overall control of the entire operation of the light 10 on thebasis of a program or the like stored in the storage unit 14.

The storage unit 14 is constituted by a nonvolatile memory or the like,such as an EEPROM (Electronically Erasable and Programmable Read OnlyMemory), for example, and stores preset control information and the likerelating to the light 10.

The communication unit 15 includes a communication interface circuit forconnecting the light 10 to the communication network, and communicateswith the communication network. Note that the light 10 may have asimpler configuration not including the communication unit 15 and so on.

Here, using FIG. 3, the wavelengths of the light emitted by the light 10will be described. FIG. 3 shows the light absorption coefficient of eachof oxyhemoglobin, reduced hemoglobin, melanin, and water, which are themain constituent elements of a living body. On the graph in FIG. 3, thehorizontal axis shows the wavelength (nm) and the vertical axis showsthe absorption coefficient.

As shown in FIG. 3, absorption by blood (in other words, hemoglobin) ishigh in a wavelength region at or below approximately 650 nm, whileabsorption by water is high in a wavelength region exceedingapproximately 950 nm. In a wavelength region of no less thanapproximately 650 nm and no more than approximately 950 nm, meanwhile,the respective absorption coefficients of hemoglobin and water arecomparatively low. It can therefore be said that light in thiswavelength region (no less than approximately 650 nm and no more thanapproximately 950 nm) passes through a living body more easily thanlight in another wavelength region.

There are no particular limitations on the wavelengths of the lightemitted by the light-emitting unit 11 of the light 10 as long aswavelengths that pass through a living body are included therein, but asnoted above, the wavelengths preferably include wavelengths within arange of no less than approximately 650 nm and no more thanapproximately 950 nm.

Further, as shown in FIG. 3, the absorption rate of oxyhemoglobin isparticularly low in a wavelength region of no less than approximately650 nm and no more than approximately 800 nm. Therefore, the wavelengthsof the light emitted by the light-emitting unit 11 of the light 10preferably include at least a part of a wavelength region of no lessthan approximately 650 nm and no more than approximately 800 nm.

Furthermore, as shown in FIG. 3, the absorption rate of reducedhemoglobin is particularly low in a wavelength range of no less thanapproximately 800 nm and no more than approximately 950 nm. Therefore,the wavelengths of the light emitted by the light-emitting unit 11 ofthe light 10 preferably include at least a part of a wavelength regionof no less than approximately 800 nm and no more than approximately 950nm.

Moreover, as shown in FIG. 3, the absorption rate of water isparticularly low in a wavelength range of no less than approximately 650nm and no more than approximately 700 nm. Therefore, the wavelengths ofthe light emitted by the light-emitting unit 11 of the light 10preferably include at least a part of a wavelength region of no lessthan approximately 650 nm and no more than approximately 700 nm.

(2-2) Optical Fiber 20

The optical fiber 20 is an example of a light guide that takes the shapeof a narrow, flexible fiber, for example, and can be inserted into theinterior of a medical tube T, as shown in FIG. 1. The optical fiber 20has a two-layer structure constituted by, for example, a central core(not shown) formed from silica glass, plastic, or the like, and cladding(not shown) covering the periphery of the central core.

As shown in FIG. 1, the incident end portion 20I through which the lightemitted by the light 10 and so on enters is formed on one end of theoptical fiber 20. The incident end portion 20I is positioned so as to beoptically connectable to the light 10 in a state where the optical fiber20 is inserted into the interior of the medical tube T.

Further, as shown in FIG. 1, an exit end portion 20E through which thelight exits is formed on the other end of the optical fiber 20. When theoptical fiber 20 correctly reaches the stomach while inserted into theinterior of the medical tube T, the exit end portion 20E is disposedinside the stomach (indicated by a reference symbol S in FIG. 1).

The refractive index of the core of the optical fiber 20 is set to behigher than the refractive index of the cladding of the optical fiber20. Accordingly, the light entering through the incident end portion 20Iis totally reflected on the boundary between the core and the claddingso as to propagate through the core. Having propagated through the coreand reached the exit end portion 20E, the light exits through the exitend portion 20E. Having exited through the exit end portion 20E, thelight passes through the stomach and other body parts and exits theliving body so as to partially reach the camera 30.

(2-3) Camera 30

FIG. 4 is a schematic view showing an example of a functionalconfiguration of the camera 30.

The camera 30 is an example of an imaging unit that generates image databy capturing an image of the living body (including a part of the livingbody) on the basis of at least the light that passes through the livingbody after exiting through the exit end portion 20E of the optical fiber20. The camera 30 includes, for example, an image sensor 31, aprocessing unit 32, a storage unit 33, and a communication unit 34. Thecamera 30 may be a camera that is particularly sensitive to infraredrays, for example.

The image sensor 31 is constituted by a CCD (a Charge Coupled Device), aCMOS (a Complementary Metal Oxide Semiconductor), or the like, forexample, and under the control of the processing unit 32, the imagesensor 31 detects light that has been condensed by a lens, not shown inthe figure, and converts the light into an electric signal.

The processing unit 32 is a CPU or the like, for example, having one ora plurality of processors and corresponding peripheral circuits, andperforms overall control of the entire operation of the informationprocessing device on the basis of a program or the like stored in thestorage unit 33. The processing unit 32 generates image data on thebasis of the electric signal generated by the image sensor 31, forexample. Further, the processing unit 32 transmits the generated imagedata to the user terminal 40 or the database 50 via the communicationunit 34.

The storage unit 33 includes at least one of a magnetic tape device, amagnetic disk device, and an optical disk device, for example, andstores a computer program, data, and so on used in the processingexecuted by the processing unit. The storage unit 33 is an example of animage data storage unit for storing the image data generated when thecamera 30 captures an image of the living body.

The communication unit 34 includes a communication interface circuit forconnecting the camera 30 to the communication network, and communicateswith the communication network.

Note that the camera 30 may also include a display unit (not shown) fordisplaying the image data generated by the processing unit 32 and so on.

(2-4) User Terminal 40

FIG. 5 is a schematic view showing an example of a functionalconfiguration of the user terminal 40. The user terminal 40 may be anygeneral-purpose information processing terminal and includes, forexample, a communication unit 41, a storage unit 42, a processing unit43, an operation unit 44, a display unit 45, and so on.

The communication unit 41 includes a communication interface circuit forconnecting the user terminal 40 to the communication network, andcommunicates with the communication network.

The storage unit 42 includes at least one of a magnetic tape device, amagnetic disk device, and an optical disk device, for example, andstores a computer program, data, and so on used in the processingexecuted by the processing unit. The storage unit 42 is an example ofthe image data storage unit for storing the image data generated whenthe camera 30 captures an image of the living body.

The processing unit 43 is a CPU or the like, for example, having one ora plurality of processors and corresponding peripheral circuits, andperforms overall control of the entire operation of the informationprocessing device on the basis of a program or the like stored in thestorage unit. The processing unit 43 may determine whether or not theposition of the medical tube T is appropriate by analyzing image datareceived from the camera 30 over the communication network. Further, theprocessing unit 13 may transmit the image data received from the camera30 over the communication network to the database 50, for example.Furthermore, the processing unit 13 may transmit a control signal forswitching the switch of the light 10 ON and OFF to the light 10, forexample.

The operation unit 44 is constituted by a touch panel, key buttons, orthe like, for example, and serves to receive operations performed by auser to input alphabetic characters, numerals, symbols, and so on andsupply signals corresponding to the operations to the processing unit.

The display unit 45 is constituted by a liquid crystal display, anorganic EL (Electro-Luminescence) display, or the like, for example, anddisplays images based on display data supplied from the processing unitand so on.

(2-5) Database 50

The database 50 is a database managed by a medical institution such as ahospital, for example, and includes at least one of a magnetic tapedevice, a magnetic disk device, and an optical disk device. The database50 receives image data from the camera 30 or the user terminal 40, forexample, and stores the received image data. In other words, thedatabase 50 is an example of the image data storage unit for storing theimage data generated when the camera 30 captures an image of the livingbody. The database 50 may be connected to an external informationprocessing device, such as a management server used by a medicalinstitution or the like, for example, via a communication network. Theexternal information processing device may obtain the image data storedin the database 50 and execute processing corresponding to various aimson the image data.

(3) Use Method and Operation

Next, a use method and an operation of the medical tube positionconfirmation system 1 will be described.

First, an operator checks the end portion of the medical tube T in thenasal cavity or the like of the patient and then inserts the opticalfiber 20 into the interior of the medical tube T by a predeterminedlength, starting with the exit end portion 20E.

Next, the switch (not shown) provided on the light 10 is switched ON sothat the light 10 emits light. At this time, the operator may cause thelight 10 to emit light by operating the switch of the light 10, forexample. Alternatively, the operator may cause the light 10 to emitlight by operating the user terminal 40 so that a control signal forswitching the switch of the light 10 ON is transmitted from the userterminal 40 to the light 10.

When the light 10 emits light, the light emitted by the light 10 entersthe incident end portion 20I of the optical fiber 20. The light thatenters the incident end portion 20I propagates through the interior ofthe optical fiber 20 by total reflection so as to reach the exit endportion 20E. Having reached the exit end portion 20E, the light exitsthrough the exit end portion 20E and passes through the body of thepatient.

The operator then checks the position of the light passing through thebody of the patient in order to determine whether or not the position ofthe light is a position corresponding to the stomach. When the positionof the light is a position corresponding to the stomach, it can bedetermined that the medical tube T has reaches the stomachappropriately. When the position of the light is not a positioncorresponding to the stomach or when the presence of the light cannot beconfirmed, it can be determined that the medical tube T has not reachedthe stomach. Here, the position of the light may be checked using eithera method of visual confirmation by the operator or a method employingthe image data generated by the camera 30. In the method employing theimage data generated by the camera 30, for example, the user terminal 40receives from the camera 30 the image data generated by the camera 30 onthe basis of at least the light passing through the stomach and otherbody parts. The user terminal 40 then analyzes the image data todetermine whether or not the position of the light is a positioncorresponding to the stomach.

(4) Miscellaneous

Note that generally, the optical intensity required for light to passfrom the interior of the stomach to the exterior of the body is lowerthan the optical intensity required for light to pass from the interiorof the lungs and trachea to the exterior of the body. Therefore, thelight source, such as the light 10, may be set to emit light at anintensity that equals or exceeds a first intensity required for light topass from the interior of the stomach to the exterior of the body but islower than a second intensity required for light to pass from theinterior of the lungs and trachea to the exterior of the body. Accordingto this configuration, there is no need to determine the position of thestomach during visual confirmation of the light by the operator oranalysis of the image data, and it can be determined that the medicaltube T has appropriately reached the stomach simply by determiningwhether or not the light can be confirmed.

The embodiment described above is to be used to facilitate understandingof the present invention, and the present invention is not limitedthereto. The elements included in the embodiment, as well as thearrangements, materials, conditions, shapes, sizes, and so on thereof,are not limited to the cited examples and may be modified asappropriate. Moreover, configurations illustrated in differentembodiments may be partially replaced or combined.

REFERENCE SIGNS LIST

-   1 Medical tube position confirmation system-   10 Light-   11 Light-emitting unit-   12 Drive circuit-   13 Processing unit-   14 Storage unit-   15 Communication unit-   20 Optical fiber-   20I Incident end portion-   20E Exit end portion-   30 Camera-   31 Image sensor-   32 Processing unit-   33 Storage unit-   34 Communication unit-   40 User terminal-   41 Communication unit-   42 Storage unit-   43 Processing unit-   44 Operation unit-   45 Display unit

1. A medical tube position confirmation system for confirming theposition of a medical tube that is used to supply nutrients to theinterior of a body by means of tube feeding while an end portion thereofis inserted into (placed in) the stomach, the system comprising: a lightguide that is configured to guide light entering through an incident endportion so that the light exits through an exit end portion, and isconfigured to be insertable into the medical tube so that the exit endportion is disposed in the interior of the stomach; and a light sourcethat is optically connected to the incident end portion of the lightguide and emits light containing wavelengths that pass through a livingbody, wherein the light source is set to emit light at an intensity thatequals or exceeds a first intensity required for light to pass from theinterior of the stomach to the exterior of the body but is lower than asecond intensity required for light to pass from the interior of thelungs and trachea to the exterior of the body.
 2. (canceled)
 3. Themedical tube position confirmation system according to claim 1, furthercomprising an imaging unit for capturing an image of the living body onthe basis of at least the light that exits through the exit end portionof the light guide and passes through the living body.
 4. The medicaltube position confirmation system according to claim 3, furthercomprising an image data storage unit for storing image data generatedwhen the imaging unit captures an image of the living body.
 5. A methodof confirming the position of a medical tube that is used to supplynutrients to the interior of a body by means of tube feeding while anend portion thereof is inserted into (placed in) the stomach, whichcomprises the steps of: inserting a light guide configured to guidelight entering through an incident end portion so that the light exitsthrough an exit end portion into the medical tube by a predeterminedlength, starting with the exit end portion; optically connecting a lightsource that emits light containing wavelengths that pass through aliving body to the incident end portion of the light guide; and causingthe light source to emit light.